I'm reasonably certain all wild orchids regardless of species in the UK are protected under CITES, so the only way you could harvest roots to make salep these days is to grow them yourself in land specially set by for harvesting, and even then, you may need extensive paperwork to satisfy the CITES regulations,especially if you share or trade the results with anyone else. Always been curious what it tastes like though, but not willing to run foul of that particular set of regulations to find out